Question for anyone who went far on Become a Legend mode!

My background:
I'm doing fine, SS/CF, scoring hat tricks, braces, giving assists, playing the UCL with Milan, being MOTM a lot of times, with a 7.2 average rating, with lots of 8.0s and 7.5s.
I also had a good start, without even knowing that I could make different combinations to start with better stats. I just accepted the first stats they gave me, and those were OK, 72 total, I guess.

I'm completely happy with my shooting and dribbling stats for now. I've got a 90 dribbling speed stat and that, combined with a 87 dribbling accuracy, is awesome for my playing style. I also have 85, 88, and 89 in shoot acc, power and tech respectively. With these stats, I can score a lot, even shooting without too much space from not too close.

But my body balance is 75, and my technique is 74. Agility is 73, and defense 45. I've spent most of my first two seasons training shooting and dribbling. I also trained a lot of power, because I started with 64 in body balance.
But these stats are too low for me!

75 body balance, 73 agility and 74 technique makes it too hard for me to receive the ball and quickly escape from my marker's approach to have some space to think.
When I played Bundesliga, it was OK, but now I went to Serie A, and I always have 2-3 players closing by when I get the ball.
If I try to be quick, my 73 agility makes my legend really sluggish.
If I try to protect the ball with my body or run, I quickly get knocked down because my low body balance makes me lose every contact with other players.
Also, my 74 technique makes it difficult to trap the ball nicely, giving time for the opposition to get really close as I try to position myself for the action I'm intended to do.

In my first and second seasons, my stats grew really fast.
But now they're growing at turtle speed. I'm not even 20 yet, but if I go on this rythm, I can't see myself growing too much but 1 or 2 points by season. My speed stats aren't even growing anymore!

Do you people know for how long I can still grow on BAL? Does it have a pattern or varies from legend to legend? If I see myself stopping my growth at 21, I know I won't be a true legend, but just a good average player. I'd like to be like Romario, Maradona, Rivaldo, not just another Kluivert or Trezeguet.

I thought it would be something dynamic, the better I play, the faster I grow, but after a second season with 7.1 average rating, winning the domestic Cup, being chosen as MVP, and being top scorer of the League, I just slowed down on growing.

And after being rated 8.0 in my last 5 consecutive games, with 3 hattricks, 2 braces, and 4 assists, I'm still pretty much at the same place.
I understand that good technique is something for a chosen few, but I'd like to improve my body balance, at least to 80. But no matter if I put 6 bars on power, it just keeps growing 2% by match.